I had the infamous number plate problem on my 330 saloon. After reading several posts, about the bulb holders corroding and failing I thought I would have a go at fixing them instead of shelling out £70 for an unpainted unit that could suffer the same fate! After reading DailyDoggys post about fitting number plate lights from a coupe unit I had a search on the net and found festoon bulb holders on ebay, 99p each plus £1 delivery from Hong Kong. I bought 2 and the delivery was £1.70. The plastic is good quality and the connectors appear to be stainless steel. Here is the link;
What you will need;
2 bulb holders & bulbs if yours are also missing! (The bulbs for the boot lights are the same size)
Dremmel style multi tool
Suitable wire for a 12v, 5 amp circuit. (Halfords)
Solder & Flux
Glue gun/grip fill
Patience and a beer!!
What I did was;
1. Remove the 4 torx screws holding the number plate light to the car.
2 Pull the unit out you may be lucky enough to pull the wire out far enough to access the connection which is about 12 inches from the unit itself, don't pull too hard. If like me you can't see the connector proceed to step 3
3. Remove the boot carpet, so working inside the boot now. Remove the trim clips, ideally you need a trim removal tool. The trim clips are in 2 parts, you need to remove the top part. To do so you need to seperate the top part so push the tool BETWEEN the top part and the piece in contact with the carpet. Pull the first part out which is T shaped then remove the second part. A bit hard to explain but should be clear when you do it.
Now remove the two screws at the base of the toolkit which are cleverly disguised to look like the carpet. The whole lot should come away now.
4. If you look where the carpet was you should see the electrilcal connector for the number plate light, unclip this and you should be able to remove the number plate assembley.
5. Peel back the adhesive foam on the back, you need a screwdriver or kitchen knife to seperate the adhesive from the handle.
6. You need to pop the grey fubared light units from the black plastic, it should just push out with a small screwdriver to lever it a bit.
7. Remove the wires from the old units. Just cut the copper tracks and remove the wires. On mine one of the units has 4 wires and the other 3, you must remember how they were connected for the new light units. With a wire stripper strip away about 1/2 inch and tape them together as they were connected.
8. Now using the new light unit as a guide you need to use your dremmel tool to make the gap wider, you want it to fit snugly.
9. Grab you new units and solder a small length (3 inches) to one of the connectors on each of the units.
10. I had to extend one of the pairs of wires as there was not enough length to reach the other connector on the new bulb unit. So if you need to solder a small length to the original wires.
11. Now solder the wires together you want a bit of slack near the boot release button. Push the wiring connectors on the new lights so they are flush. GO AND CHECK THE LIGHTS WORK BEFORE PROCEEDING!!
12. Once you have soldered the wires you need to glue in the new light units, I used grip fill as I don't have a glue gun. But contact adhesive may work. Leave it to dry.
13. I also put clear silicone on the connectors to try and stop further corrosion. It will get hot when the bulb will be on so not sure if that was a good idea!
14. Refit to the car and admire your handy work that has cost you £5 and a few hours